A jazz band is playing on the quayside as people drink champagne from paper cups. Girls in shorts and bikini tops are basking in the May sunshine. Others are milling around the trendy craft and clothes shops or having lunch alfresco at the water's edge. The Daphne du Maurier Festival is in full swing in the Cornish resort of Fowey.

A few miles down the road people are queuing to get into the Eden Project. A little over two months since its opening, Eden's giant greenhouses, or biomes, have already become one of the UK's top 10 tourist attractions with more than 330,000 visitors. At a time when the rest of the country's tourism industry has been suffering from the effects of the foot and mouth outbreak, Eden is being regarded as Cornwall's saviour.

With Devon hit badly by the disease - the worst-affected county after Cumbria with 165 cases - tourist chiefs feared few people would be prepared to journey through the county to Cornwall, which only had four cases. But they were wrong. At Easter more than 42,000 people visited the attraction in four days, causing massive tailbacks on the county's roads.

'I think a lot of people have been saying thank the Lord for Eden,' says South West Tourism's chief executive Malcolm Bell. 'In the first few weeks of the outbreak Cornwall was hit as badly as everywhere else but the opening of Eden has helped tourism to bounce back.The whole curse of foot and mouth was that it put people off going anywhere. Eden gave people a reason to go.'

George Elworthy, operations manager at the Eden Project, believes the uncertainty over what was open in Cornwall in the last few months has also encouraged more people to visit. 'Foot and mouth drove people to us,' he said. It's also seen as the reason why Tate St Ives has continued to do well in a traditionally low season. Visitor numbers are up nearly 30 per cent to 52,000 since January.

So why is Eden so popular? Conservationist Simon Beeching, who has a holiday home in St Mawes, loves the interactive exhibits. 'Conservation without education is pointless. Watching the kids learn about what the world would be like without plants gives them a better understanding,' he said.

The £86 million project has also been compared favourably with the Millennium Dome. While the Dome was horribly corporate with every zone sponsored, Eden has managed to maintain its integrity and use as many local products as possible. 'Before we opened we had all the major ice-cream manufacturers wanting us to sell their products, but we preferred to sell local Cornish ice cream,' said Elworthy.

Liberal Democrat leader Charles Kennedy chose the Eden Project as the launch pad for his party's environmental policy; not something many politicians would have been falling over themselves to do at the Dome if it was still open.

One of the most notable things about Eden is its power to encourage repeat visitors, many of whom were eager to see the project months before it opened. It will always be a work in progress as the landscaped gardens become more established and the plants in the tropical and temperate biomes continue to grow.

When I visited Eden, Christopher Salter and his partner Jill Burn, from Wadebridge, were on their twelfth visit. 'We came a few times before it even opened. The great thing is that it keeps changing every time we come back. We think it's absolutely brilliant,' said Salter.

Eden's pulling power has not just benefited the surrounding area. Resorts as far away as Padstow and Newquay on the north coast are marketing Eden short breaks with great success. 'I've discovered friends and relatives I didn't realise I had since the Eden Project opened,' said Paul Wright, head of tourism for Restormel Borough Council in Newquay.

In upmarket Fowey, a 15-minute drive from Eden, business is booming. Rob Husband, manager of the King of Prussia public house, said: 'I was worried about the foot and mouth when it first started but the Eden Project has made us busier than ever. We used to call the afternoon shift the dead shift but it isn't any more.'

Taxi driver Mike said: 'If it wasn't for Eden we would have been really, really quiet. We usually attract lots of walkers during the Spring but not many have come this year because the footpaths have been closed.'

James Coggan, manager of the Marina Hotel, which overlooks Fowey estuary, said bookings from America have fallen off in the last couple of months but the growth in Eden short breaks had more than made up for the shortfall.

The number of cruise liners coming into Fowey is also increasing this summer. Last year four ships came in, this year more than a dozen are expected. A large number of them are selling day trips to Eden.

Many people regard Eden as not only bringing in the punters but also helping to build Cornwall's image as a cool place to go on holiday. Tate St Ives, Rick Stein's fish restaurant in Padstow and the chic Tresanton Hotel in St Mawes have highlighted that Cornwall can offer world-class culture, food and quality hotels as well as stunning scenery. 'Eden is very much the cherry on top of the cake,' said South West Tourism's Bell.

Since Olga Polizzi, sister of Sir Rocco Forte, opened Tresanton two years ago St Mawes has been attracting A-list celebrities, many of whom have fallen in love with the area's natural beauty.

The likes of Pierce Brosnan have been helicoptered in to the upmarket hotel and actress Kate Winslet is rumoured to be interested in buying a home in the area. An advert in the window of estate agent Millers Countrywide in St Mawes on behalf of an anonymous couple says they are prepared to pay up to £1m for a waterside property on the picturesque Roseland Peninsula.

Gloria Hunniford and her daughter Caron Keating have bought houses in Fowey and Gloria's buddy Sir Cliff Richard is understood to be looking for a waterside property.

It's the same story on the north coast in Rock, where Posh and Becks are reported to be looking for a manor house. A great favourite with Prince William, many Londoners have been buying second homes in Rock, now dubbed Chelsea by the Sea.

Newquay is now known more for its surfing competitions than as a destination for coach tourists. The town has more than 30 shops selling surfing gear.

Many regard Eden's creator Tim Smit as helping to bring a new professionalism to Cornwall's tourist industry. He has made people realise they have to offer a quality product to compete. 'Cornwall can't afford to stay in the dark ages and have bad food and service. It has got to change and it is beginning to happen,' said Richard Davies, trainee manager at the Galleon public house in Fowey. 'Especially when you can go abroad for £150.'

This week Eden Project staff hope they are more prepared for the Spring Bank Holiday and school half-term holidays than they were for the influx at Easter. Extra staff have been recruited, opening hours extended and ticket booths doubled to cope with the expected influx. Car parks are also being built.

This weekend also sees the majority of the county's coastal footpaths and other rights of way reopening to the public, sending out a positive message for people planning their summer holidays. It looks like Cornwall might ride the storm after all.

Fact file

The Eden Project (01726 811911). Tickets cost £9.50 for adults and £4 for children (5-15 years).